It will be the aim of this research project to compare the composition of oviductual fluid collected by continuous flow method (Hammer & Williams, 1965) from different segments of the rabbit oviduct under various hormonal states. The effect of these fluids on fertilization, ova cleavage and development will be determined by in vivo and in vitro culture techniques. Emphasis will be placed on those constituents of oviduct fluid that are essential to early embryo development and transfer of in vitro developed embryos to foster mothers.